| In modern cities, elevator is a closest companion to DHHGY customers as well as an indispensable travel tool, which is equally important as water, electricity, gas and other necessities of life. With the continuous improvement of people's living standard, increasingly high expectations of elevator are widespread concerned, especially the reliability, ride comfort, energy conservation and operating speed. To improve the operation efficiency and service quality, it needs in-depth studies to improve elevator controller and speed governing approaches.Due to low reliability, bulky size and slow response, traditional relays in elevator control systems have basically been eliminated, and replaced by programmable logic controllers. With the development of power electronics technology and microelectronic technology, it is an indisputable fact that AC speed governing has been replaced by DC drive. In AC Drive Speed Control System mode, AC VVVF with advantages of easy speed-governing and energy-saving compares favourably with DC VVVF, so it is widely used in various fields and becomes the mainstream of motor speed governing. In this paper, frequency control of motor speed based on programmable logic controller is applied to the elevator control system, which is got deep reachesPrinciples of programmable controller and frequency control technology are presented. According to six-story elevator control requirements, implementation of VVVF elevator control system is proposed based on S7-200 PLC and common uuivertor FR-A540. Then the influence of lift car running S-shaped curve to the elevator comfort is analyzed as well as the positioning control of rotary encoder. However,VVVF elevator drive system and controller design are the focal points. The simulation debugging results show that elevator conversion speed governing system has g ot a good comfort. based on PLC is running stable, easy to be transformed, positioning accuracy, and also...
|
PDF Full Text Request